Cell density profile data does not allow us to uniquely estimate D and q . All results correspond to experiments where cells were pretreated with Mitomycin–C to prevent cell proliferation. Cell density profiles were extracted from each experiment by partitioning the transect into 98 rectangular regions. The transect is the dark region shown in (A) passing through the entire cell colony. The scale bar corresponds to 1.5 mm. The magnified image inset in (A) shows several cells which have been identified by image analysis software (white dots). Experimental transects at t=0 and t=48 hours are shown in (B) and (D) for experiments initialised with 20,000 cells. The scale bar corresponds to 1.5 mm. Histograms showing the experimental cell density profile along the transect are shown in (C) and (E). Each experimental cell density profile was averaged using three experiments as described in the text. The corresponding model predictions are superimposed at t=0 hours in (C) and at t=48 hours in (E) using five identically–prepared realisations of the model. Both curves correspond to simulations where D=243μ m2hour−1. The red curve in (E) corresponds to weak cell–to–cell adhesion (q=0.1) and the green curve corresponds to strong cell–to–cell adhesion (q=0.9). The leading edge in (E) is magnified in (F). The error surfaces in (G) and (H) show Error
(D,q), given by Equation 4, for various values of D and q. Simulation results are averaged over five identically–prepared realisations. The red and green crosses in (G) correspond to the two model solutions superimposed in (E).